<%if webaddress.categories.include?(category) %>
<%= link_to_remote image_tag('/images/greenball.gif', :title => h(category.name)),
                   :update => "toggle-#{webaddress.id}-#{category.id}",
                   :url => {:action => :remove_association,
                                 :id => "#{webaddress.id}-#{category.id}",
                                 :method => :post} %>
<% else %>
<%= link_to_remote image_tag('/images/redball.gif', :title => h(category.name)),
                   :update => "toggle-#{webaddress.id}-#{category.id}",
                   :url => {:action => :add_association,
                            :id => "#{webaddress.id}-#{category.id}",
                            :method => :post} %>
<% end %>
